On a loan, or on a credit card application?
How long have you been working at your job? Is it a consistent paycheck or does it fluctuate? Does somebody in your immediate family have serious problems with credit?
Have you run your free credit reports to ensure nobody opened credit in your name and that's the reason you're being blocked?
I've been at my current job 1.5 years. The pay is consistent (salary). At the time I applied I had a worse job and wasn't there for as long. I have checked my credit and I had an avg score of 620 just before I started my current job (1 year ago) but I have had no revolving credit other than a car payment which got paid off last June.
I got reported on a loan I failed to repay in 2003, which I paid off in 2005.